When we say herbal teas, we don’t  imply basic tea but mostly  infusions and decoctions.

Tea is an important dietary source of flavanols and flavonols. Tea polyphenols may possess the bioactivity to affect the pathogenesis of several chronic diseases, especially cardiovascular disease and cancer.When we brew tea, we may loose the enzymatic component of the plants to heat, but we are able to extract potent phytonutrient that have potent anti-tumor properties that do not co exist with cancer cells in the same environment.  They can selectively destroy cancer cells while nourishing healthy cells. These alkaloids or secondary compounds in tea called catechins have potent antioxidant activity to help reduce the risk of cancer by fixing cell damage. Among other roles, catechins have been shown to inhibit growth of tumor cells and keep them from spreading to other parts of the body. Tea is the best source of catechins in the human diet and for a variety of tea blends click on this link

One reason the Japanese have the highest tobacco smoking rate but the lowest lung cancer rate, could be green tea. The tea contains epigallocatechin gallate, theophylline, tannic acid and other polyphenols, which have been shown to inhibit cancer growth .Green tea's ability to fight cancer is even more potent and varied than scientists suspected, say researchers who have discovered that chemicals in green tea shut down one of the key molecules that tobacco relies upon to cause cancer. It's a find that could help explain why people who drink green tea are less likely to develop cancer.

 The finding by scientists at the University of Rochester's Environmental Health Science Center appears in the July 21 issue of Chemical Research in Toxicology, published by the American Chemical Society.Graduate student Christine Palermo and adviser Thomas Gasiewicz, Ph.D., set out to measure the effects of the chemicals found in green tea on a molecule known as the aryl hydrocarbon (AH) receptor, a molecule that frequently plays a role in turning on genes that are oftentimes harmful. Gasiewicz has previously shown how both tobacco smoke and dioxin manipulate the molecule – a favorite target of toxic substances – to cause havoc within the body. The team isolated the chemicals that make up green tea and found two that inhibit AH activity. The two substances, epigallocatechingallate (EGCG) and epigallocatechin (EGC), are close molecular cousins to other flavonoids found in broccoli, cabbage, grapes and red wine that are known to help prevent cancer.

 Scientists do know that green tea contains chemicals that are anti-oxidants and quench harmful molecules. But its effects on the AH receptor have not been thoroughly evaluated until now."It's likely that the compounds in green tea act through many different pathways," says Gasiewicz, professor and chair of Environmental Medicine and director of Rochester's Environmental Health Science Center. "Green tea may work differently than we thought to exert its anti-cancer activity."Gasiewicz and Palermo showed that the chemicals shut down the AH receptor in cancerous mouse cells, and early results indicate the same is true in human cells as well. In the laboratory the AH-inhibiting effects of green tea become evident when EGCG and EGC reach levels typical of those found in a cup of green tea. But the scientists say that how green tea is metabolized by the body is crucial to its effectiveness, and that results in the laboratory don't necessarily translate directly to the dinner table.  Green Tea’s Cancer-fighting Allure Becomes More Potent ScienceDaily (August 2005)

Laboratory studies have demonstrated inhibitory effects of tea preparations and tea polyphenols against tumor formation and growth. This inhibitory activity is believed to be mainly due to the antioxidative and possible antiproliferative effects of polyphenolic compounds in green and black tea. These polyphenolics may also inhibit carcinogenesis by blocking the endogenous formation of N-nitroso compounds, suppressing the activation of carcinogens, and trapping of genotoxic agents.

Supplement makers have responded to the positive results of tea research with a multitude of tea extracts. Perhaps the most popular, epigallocatechin gallate (EGCG) is popping up in a variety of nutritional supplements, from multivitamins to herbal concoctions. Though EGCG may have some benefit, it should be used in moderation. Very high amounts of green tea components have been shown to interact with drugs that affect blood clotting such as aspirin, and also may cause liver damage.

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